4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "David S. Miller" <da...@davemloft.net>


[ Upstream commit 7dd7eb9513bd02184d45f000ab69d78cb1fa1531 ]

Do not use unsigned variables to see if it returns a negative
error or not.

Fixes: 2423496af35d ("ipv6: Prevent overrun when parsing v6 header options")
Reported-by: Julia Lawall <julia.law...@lip6.fr>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/ipv6/ip6_offload.c |    9 ++++-----
 net/ipv6/ip6_output.c  |    7 +++----
 net/ipv6/udp_offload.c |    8 +++++---
 3 files changed, 12 insertions(+), 12 deletions(-)

--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -62,7 +62,6 @@ static struct sk_buff *ipv6_gso_segment(
        const struct net_offload *ops;
        int proto;
        struct frag_hdr *fptr;
-       unsigned int unfrag_ip6hlen;
        u8 *prevhdr;
        int offset = 0;
        bool encap, udpfrag;
@@ -121,10 +120,10 @@ static struct sk_buff *ipv6_gso_segment(
                skb->network_header = (u8 *)ipv6h - skb->head;
 
                if (udpfrag) {
-                       unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
-                       if (unfrag_ip6hlen < 0)
-                               return ERR_PTR(unfrag_ip6hlen);
-                       fptr = (struct frag_hdr *)((u8 *)ipv6h + 
unfrag_ip6hlen);
+                       int err = ip6_find_1stfragopt(skb, &prevhdr);
+                       if (err < 0)
+                               return ERR_PTR(err);
+                       fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
                        fptr->frag_off = htons(offset);
                        if (skb->next)
                                fptr->frag_off |= htons(IP6_MF);
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -571,11 +571,10 @@ int ip6_fragment(struct net *net, struct
        int ptr, offset = 0, err = 0;
        u8 *prevhdr, nexthdr = 0;
 
-       hlen = ip6_find_1stfragopt(skb, &prevhdr);
-       if (hlen < 0) {
-               err = hlen;
+       err = ip6_find_1stfragopt(skb, &prevhdr);
+       if (err < 0)
                goto fail;
-       }
+       hlen = err;
        nexthdr = *prevhdr;
 
        mtu = ip6_skb_dst_mtu(skb);
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -29,6 +29,7 @@ static struct sk_buff *udp6_ufo_fragment
        u8 frag_hdr_sz = sizeof(struct frag_hdr);
        __wsum csum;
        int tnl_hlen;
+       int err;
 
        mss = skb_shinfo(skb)->gso_size;
        if (unlikely(skb->len <= mss))
@@ -97,9 +98,10 @@ static struct sk_buff *udp6_ufo_fragment
                /* Find the unfragmentable header and shift it left by 
frag_hdr_sz
                 * bytes to insert fragment header.
                 */
-               unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
-               if (unfrag_ip6hlen < 0)
-                       return ERR_PTR(unfrag_ip6hlen);
+               err = ip6_find_1stfragopt(skb, &prevhdr);
+               if (err < 0)
+                       return ERR_PTR(err);
+               unfrag_ip6hlen = err;
                nexthdr = *prevhdr;
                *prevhdr = NEXTHDR_FRAGMENT;
                unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +


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